After the main USI student protest on Merrion Square ended, some of the crowd moved up Merrion Street and around the corner onto Merrion Row, where a group of protestors had entered the lobby of the Department of Finance.

This video is a record of the events which followed. It contains violence and strong language.

This Irish Times timeline of the events of the day seems pretty accurate:

Student march: timeline of events

1pm:

The march began at Parnell Square. Gardaí have estimated the crowd at 15,000, whereas the Union of Students in Ireland put the figure at over 40,000.

1.40pm:

A small group departed early from the march route along Nassau Street and went straight to the front gates of the Dáil on Kildare Street [MAP 4], where some protesters climbed poles and threw plastic